Sorted By Test Name - Mayo Medical Laboratories

ACAR
82850
in soil and fresh water sources. Naegleria fowleri may enter the central nervous system (CNS) during
exposure to infected water and cause a fulminant meningitis in previously healthy individuals. In contrast,
Acanthamoeba species and Balamuthis mandrillaris cause chronic granulomatous encephalitis in
immunocompromised (and, rarely, immunocompetent) adults, and typically disseminate to the CNS from
a primary lung or skin source. Acanthamoeba species can also cause a painful keratitis when organisms
are introduced into the eye. This typically occurs during contact lens use when the lenses or storage or
cleaning solutions are contaminated. Amebae can also enter the cornea with abrasion or trauma. Amebic
keratitis can cause blindness if untreated. Most cases respond to treatment once a diagnosis is made, but
some cases prove to be resistant to therapy with no antimicrobials uniformly active against the organisms.
Useful For: Diagnosis of Acanthamoeba species and Naegleria fowleri, in central nervous system or
ocular specimens
Interpretation: Organisms seen on stains of the original specimen smear or growth on culture media
are positive tests.
Reference Values:
EYE
Negative for Acanthamoeba species
CENTRAL NERVOUS SYSTEM
Negative for Acanthamoeba/Naegleria species
Clinical References: 1. Acanthamoeba keratitis multiple states, 2005-2007. MMWR Morb Mortal
Wkly Rep 2007;56(21):532-534 2. Kumar R, Lloyd D: Recent advances in the treatment of
Acanthamoeba keratitis. Clin Infect Dis 2002 Aug 15;35(4):434-441 3. Yoder JS, Eddy BA, Visvesvara
GS, et al: The epidemiology of primary amoebic meningoencephalitis in the USA, 1962-2008. Epidemiol
Infect 2009 Oct;22:1-8 4. Schuster FL: Cultivation of pathogenic and opportunistic free-living amebas.
Clin Microbiol Rev 2002 Jul;15(3):342-354
Acarus siro, IgE
Clinical Information: Clinical manifestations of immediate hypersensitivity (allergic) diseases are
caused by the release of proinflammatory mediators (histamine, leukotrienes, and prostaglandins) from
immunoglobulin E (IgE)-sensitized effector cells (mast cells and basophils) when cell-bound IgE
antibodies interact with allergen. In vitro serum testing for IgE antibodies provides an indication of the
immune response to allergen(s) that may be associated with allergic disease. The allergens chosen for
testing often depend upon the age of the patient, history of allergen exposure, season of the year, and
clinical manifestations. In individuals predisposed to develop allergic disease(s), the sequence of
sensitization and clinical manifestations proceed as follows: eczema and respiratory disease (rhinitis and
bronchospasm) in infants and children less than 5 years due to food sensitivity (milk, egg, soy, and wheat
proteins) followed by respiratory disease (rhinitis and asthma) in older children and adults due to
sensitivity to inhalant allergens (dust mite, mold, and pollen inhalants).
Useful For: Testing for IgE antibodies may be useful to establish the diagnosis of an allergic disease
and to define the allergens responsible for eliciting signs and symptoms. Testing also may be useful to
identify allergens which may be responsible for allergic disease and/or anaphylactic episode, to confirm
sensitization to particular allergens prior to beginning immunotherapy, and to investigate the specificity of
allergic reactions to insect venom allergens, drugs, or chemical allergens.
Interpretation: Detection of IgE antibodies in serum (Class 1 or greater) indicates an increased
likelihood of allergic disease as opposed to other etiologies and defines the allergens that may be
responsible for eliciting signs and symptoms. The level of IgE antibodies in serum varies directly with the
concentration of IgE antibodies expressed as a class score or kU/L.
Reference Values:
Class IgE kU/L Interpretation
0 Negative
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